The present invention relates to an earthing stud designed as a weld stud for the application of a cable terminal with cable holder.
Known weld studs have a shank and a flange adjacent thereto, the flange having, on its side remote from the shank, a weld face which serves for welding the weld stud onto a metallic article or a metal plate. Such weld studs are used, for example, in the production of motor vehicles for fastening brake tubes, fuel lines and electric leads. If electric leads are to be fastened, the shank preferably has an external thread, the lead is arranged via a cable holder on a cable terminal, and the cable terminal is fastened on the shank by means of a nut.
A problem which repeatedly poses problems in the fastening of components on weld studs resides in the fact that the components are generally inadequately protected from twisting. Forces and torques of greatly different natures and values act upon the components held by the weld studs owing to the vibrations originating during movement of the vehicle body. As already described in German Gebrauchsmuster application G 84 25 599.4, these torques can lead to twisting of the component relative to the weld stud. The component is therefore loosened, particularly if the shank has spiral projections, i.e. a thread, so that the component can no longer fulfil its function to an optimum. According to the above-mentioned Gebrauchsmuster application, a non-rotatable connection between component and weld stud and a reliable, correctly positioned assembly is achieved in that the shank is divided into two immediately adjacent regions, the first region being provided with substantially radially encircling projections for absorbing an axial force and the second region having several beads for absorbing a torque, these beads being parallel to the axis, being distributed round the periphery, having an external diameter which is greater than the corresponding internal diameter of the bore of the component and pressing themselves in the bore of the component.
If the component to be fastened, for example a cable terminal, has an extremely small height, this specified solution to the problem is unsuitable. The second region, provided on the flange of the weld stud, with beads, parallel to the axis, should have an equally small height as the component to guarantee that axial displacement cannot occur. However, this is accompanied by problems in production and has the further disadvantage that weld studs of different designs would have to be provided for each different height of different cable terminals. Furthermore, cable terminals are normally produced from a material which is not very strong so the cable terminal could be destroyed when applied to a weld stud provided with axial beads.
In the case of weld studs with a shank having only a thread and no axially parallel beads, the cable terminal is applied to the weld stud by tightening a nut arranged over the cable terminal. It may happen that the cable terminal is also rotated in a disadvantageous manner. Moreover, it can happen with an earthing stud according to the prior art that the cable terminal twists when the tightened nut is loosened in the course of time, owing to wear, which, in extreme cases, could go so far that the cable terminal or a connected cable of which the protective sheath is destroyed produces a short circuit owing to contact with another cable or component. Even though a plastic cap is generally placed over an earthing stud according to the prior art, the aforementioned problem cannot be ignored; the problem of twisting of the cable terminal during fitting of the cable terminal cannot be solved by providing a plastic cap.
It is accordingly the object of the invention to develop an earthing stud designed as a weld stud for the application of a cable terminal with cable holder such that twisting of the cable terminal is inhibited.